This 'metal' cover, if it's really 'metal' will bend from the 4 springs pressure. One of acrylic's physical property, is not to be used in a design where bending occurs. Micro-cracks will develop over time.

agreed but heat cycles causes the micro-cracking and stress on larger ones

its not sealing anything just holding block to die, cover looks plastic PM, the back plate is metal

Martin's test is done. He shows that the thermals are roughly the same as the CPU 370. No mention of Kryos HF or EK HF Ni. However, overall, this block comes in third in thermals, since both EK Ni and AC Kryos HF have consistent wins over the CPU 370. So really, not bad performance from a block that is mainly made from plastic. My only issue with the block is the acrylic mounting piece. I have seen what a little heat and pressure can do to acrylic. Note that, most people do not watercool their chipset. With the original fan + heatsink, the area around the CPU stays somewhat cool. When we use a water block, that are can get toasty. I would really like to see what would happen to that mounting system with 24/7 oc folding.

There is a note over @ XS.org's Raystorm thread saying that XSPC removed the LGA2011 compatibility from their website. Hopefully they will take care of their customers, but I realize they are not Noctua!